A 6.8-magnitude quake struck off Chile's Pacific coast overnight, followed by a large aftershock, prompting the evacuation of parts of Easter Island but causing no deaths or injuries, officials said Thursday.

The quake struck at 0215 GMT some 580 kilometers (360 miles) south of Easter Island, according to the US Geological Survey. It had a depth of 15.5 kilometers (9.6 miles).

The quake, initially measured by USGS as 7.1 on the Moment Magnitude Scale, was later revised to 6.8.

A magnitude 6.6 aftershock hit approximately the same spot just 17 minutes later at a depth of 10 kilometers, according to the USGS.

Authorities said they evacuated about 350 people from low-lying areas of the island because of the risk of a tsunami, but none developed.

Easter Island is famous for its nearly 900 massive monuments, called moai. It was named a UNESCO World Heritage Site in 1995.

Chile is one of the most seismically active countries in the world, and is located in the so-called Ring of Fire area of the Pacific Ocean basin.

An 8.2-magnitude quake in northern Chile in April killed six people and forced a million people to leave their homes in the region around Iquique.

And a February 27, 2010 quake that struck just off the coast of Chile's Maule region measured 8.8 in magnitude, making it one of the largest ever recorded.

It killed more than 500 people and inflicted an estimated $30 billion in damages.